A duplex communication system is a point-to-point system composed of two connected parties or devices that can communicate with one another in both directions. Generally, a duplex system has two clearly defined data transmission channels, with each channel carrying information in one direction. In a full duplex system, both parties/devices can communicate with each other simultaneously using the same physical spectrum channels.
In a (Radio Frequency) RF cable network, full duplex communications can be more difficult to achieve due to the number of “downstream” devices and the network configuration. For example, a Cable Modem Termination System (CMTS) is typically coupled to a plurality of downstream Cable Modems (CMs). Each of the CMs can transmit “upstream” along the same path to the CMTS while the CMTS transmits its downstream communications to the CMs. The CMs and the CMTS generally use different spectral bands. The CMs can also transmit at specific coordinated times. However, because many CMs are transmitting to the CMTS, they tend to interfere with one another as well as with the CMTS if they are not separated in time and spectrum bands, as required in Frequency Division Duplex (FDD), Time Division Multiple Access (TDMA), and Time Division Duplex methods currently practiced.